1. Field
Embodiments relate to a rechargeable battery and a battery module.
2. Description of the Related Art
A rechargeable (secondary) battery differs from a primary battery in that it can be repeatedly charged and discharged and can be classified as a low capacity rechargeable battery or a high capacity rechargeable battery. A battery module may be formed by connecting a plurality of high-capacity secondary batteries in the form of a pack and may be used as a power supply for, e.g., driving motors in hybrid electric vehicles and the like. For example, a rechargeable battery module may be formed to have necessary power by coupling a plurality of unit batteries in series.
A unit battery, that is, a rechargeable battery, may include an electrode assembly formed in a jelly roll shape formed by winding a positive electrode and a negative electrode at both sides of a separator with the separator, a case with the electrode assembly installed therein, a cap plate sealing an opening of the case, an electrode terminal electrically connected to the electrode assembly and protruding to an outside of the cap plate through a terminal hole in the cap plate, and a lead tab respectively connecting the negative electrode and the positive electrode of the electrode assembly to the electrode terminal.
There may be an insulating structure between the electrode terminal and the terminal hole of the cap plate; and the electrode terminal may be caulked and/or welded to the lead tab from the inside of the cap plate and fixed to the terminal hole by fastening with a nut at the outside of the cap plate or may be connected to the terminal hole through a bus bar. That is, the electrode terminal may be exposed to the outside of the case in the unit battery or battery module state.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the described technology and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.